High performance coupled coplanar waveguides with slow-wave features

ABSTRACT

A device including a coplanar waveguide structure is disclosed. A coplanar waveguide structure comprises one or more ground lines proximate to one or more signal lines, the signal lines and the ground lines being essentially parallel to each other and oriented substantially along a first direction; a periodic structure included in at least one of the one or more signal lines comprises alternating segments, wherein at least one of the alternating segments extends in a second direction transverse to the first direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

The entire disclosure of U.S. patent application Ser. No. 12/023,184 filed on Jan. 31, 2008, entitled “Transmitting Radio Frequency Signal in Semiconductor Structure,” related hereto and commonly assigned herewith, is hereby incorporated by reference.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling-down has also emphasized the importance of managing the transmission of radio frequency signals within such ICs. Coplanar waveguide (CPW) structures are often utilized for such transmission, however, it has been observed that conventional CPW structure performance degrades as the transmission frequency increases. Particularly, the performance of conventional CPW structures is less than desirable as electromagnetic wavelength increases. For example, the electromagnetic wavelength in a SiO₂ dielectric material is 3000 μm at 50 GHz, which is area-consuming for the application of impedance matching networks of quarter-wavelength long transmission lines. Also, conventional CPW structures currently provide no shield between a signal line and an underlying substrate, and low-loss CPW structures on a silicon substrate are designed and optimized using a thick dielectric layer, which conflicts with advanced CMOS processing. Accordingly, what is needed is a device that addresses the above stated issues.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIGS. 1A-1C illustrate a perspective view, a top view, and an equivalent circuit of an embodiment of a coplanar waveguide structure, respectively.

FIG. 2 illustrates a perspective view of an embodiment of a coplanar waveguide structure.

FIGS. 3A-3D and 4A-4C illustrate top views of a coplanar waveguide structure according to various embodiments.

FIGS. 5A-5D illustrate a transverse cross-sectional view of a device including a coplanar waveguide structure according to various embodiments.

FIGS. 6A-6C, 7A-7D, 8A-8F, 9A-9D, and 10A-10F illustrate perspective views of a coplanar waveguide structure according to various embodiments.

FIGS. 11-24 illustrate perspective views of a device including a coplanar waveguide structure according to various embodiments.

DETAILED DESCRIPTION

The present disclosure relates generally to devices including coplanar waveguide structures, and more particularly, to devices including coupled coplanar waveguide structures.

It is understood that the following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over, above, below, or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

FIG. 1 illustrates a perspective view of one embodiment of a coplanar waveguide structure 1. The coplanar waveguide structure 1 comprises one or more conductor lines 2, 4 a, 4 b. In the present embodiment, the conductor line 2 is a signal line. The signal line 2 lies between the one or more conductor lines 4 a, 4 b. The one or more conductor lines 4 a, 4 b are relatively static lines (collectively referred to as relatively static lines 4). The signal line 2 may be coupled to a wave source. The wave source may be any suitable frequency. For example, the wave source may include a radio frequency signal source and/or consumer, such as a transmitter, a transceiver, or an antenna. In some embodiments, the signal line 2 carries a radio frequency signal along its length. In some embodiments, the signal line may be designed to carry a radio frequency signal in the microwave and/or millimeter range (for example, frequencies between about 300 MHz and about 300 GHz). In the present embodiment, the relatively static lines 4 may be electrically coupled to ground, and thus, the relatively static lines 4 may also be referred to as ground lines. In some embodiments, one or more of the relatively static lines 4 may be coupled to an AC or DC voltage source, including a reference voltage source.

Signal line 2 is composed of any material capable of propagating a radio frequency signal. Ground lines 4 are composed of any material capable of shielding. For example, the signal line 2 and/or ground lines 4 may comprise metal, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof. It is understood that the signal line 2 may comprise the same or different material as the ground lines 4, and the ground line 4 a may comprise the same or different material as the ground line 4 b . In some embodiments, a region between the signal lines 2 and the ground lines 4 may comprise a dielectric or other suitable material.

Signal line 2 and ground lines 4 are oriented substantially parallel to one another in a longitudinal direction. Signal line 2 and ground lines 4 extend longitudinally a substantially uniform distance L, and signal line 2/ground lines 4 have a substantially uniform height H. In some embodiments, signal line 2/ground lines 4 may extend longitudinally varying distances L, and signal line 2/ground lines 4 may have varying heights H. For example, in some embodiments, the signal line 2 may extend a first distance, and the ground lines 4 may extend a second distance. In some embodiments, the ground line 4 a may extend a first distance and ground line 4 b may extend a second distance. The foregoing examples apply equally to the height H for the signal line 2 and ground lines 4. Each ground line 4 has a width W_(g). The ground line width W_(g) may be the same or different for each ground line 4. For example, ground lines 4 a, 4 b may be equally wide (i.e., ground line 4 a width W_(g)=ground line width 4 b W_(g)). Ground lines 4 may be wider than they are high (i.e., W_(g)>H), higher than they are wide (i.e., W_(g)<H), square (W_(g)=H), or combinations thereof.

As shown in FIG. 1, the dimensions of the signal line 2 varies along a longitudinal axis (in the present embodiment, a z-axis). The variation in dimensions of the signal line 2 forms a periodic structure in the signal line 2. More specifically, the signal line 2 includes alternating segments, a first segment 5 and a second segment 6, which form the periodic structure. The first segment 5 comprises a width W and a length D_(S). The second segment 6 extends outwardly, horizontally on either side of the signal line 2 towards ground lines 4, making the second segment 6 wider than the first segment 5. The second segment 6, extending outwardly, may form a rectangular shape, an elliptical shape, a semi-circular shape, a triangular shape, other suitable shape, and/or combinations thereof. In the present embodiment, the second segment 6 forms a rectangular shape having a length D_(L) and a width D_(W). It is understood that the second segment 6 may have different dimensions. It is further understood that, in some embodiments, the second segment 6 may extend inwardly, horizontally on either side of the signal line 2 towards the center of signal line 2. In some embodiments, the second segment 6 may extend from only one side of the signal line 2.

The periodic structure in signal line 2, formed by alternating first segments 5 and second segments 6, repeats with a period of D_(S)+D_(L). In other embodiments, the signal line 2 may have a nonperiodic structure, or it may have a structure that includes more or fewer segments. The dimensions of the coplanar waveguide structure 1 may be selected to provide a desired signal characteristic, for example, a desired phase velocity as described below. In some embodiments, the dimensions W, D_(S), D_(L), and D_(W) may each be between about 0.1 μm and about 8 μm.

The electrical and radio frequency characteristics of the coplanar waveguide structure 1 in FIG. 1 will now be described by making reference to FIGS. 1B and 1C. Using distributed circuit theory, the coplanar waveguide structure 1 may be modeled using a series of equivalent circuits. For each differential unit length dz, the coplanar waveguide structure 1 may be treated as if it were comprised of an equivalent circuit, such as the equivalent circuit illustrated in FIG. 1C. The equivalent circuit has an inductance per unit length L and a capacitance per unit length C. The equivalent circuit may also have a resistance per unit length R and a conductance per unit length G. Thus, the coplanar waveguide structure 1 may be described using line parameters based on electric circuit concepts.

The values of L, R, C, and G may be determined from the physical characteristics of the coplanar waveguide structure 1, including its physical dimensions and material composition. The phase velocity V_(p) of a wave traveling along the signal line may be expressed as:

$\begin{matrix} {V_{p} = \frac{c}{\sqrt{ɛ_{r}\mu_{r}}}} \\ {= \frac{1}{{n/2}\sqrt{LC}}} \end{matrix}$

where c is the speed of light, ε_(r) is the relative permittivity, and μ_(r) is the relative permeability. Thus, to design a coplanar waveguide structure to have a desired phase velocity, the materials for the coplanar waveguide may be chosen to provide a desired relative permittivity and permeability. Alternately, the coplanar waveguide structure may be dimensioned to provide the desired inductance and capacitance using the structures disclosed herein.

In the present embodiment, the periodic structure, comprising alternating segments 5, 6, provides alternating respective high and low impedance sections as illustrated in the equivalent circuit shown in FIG. 1C. If the alternating high and low impedance sections are short in length compared to the wavelength, and the alternating segments are cascaded together, the inductance is dominated by the high impedance section, and the capacitance is dominated by the low impedance section. For example, if the wavelength is approximately 3000 μm at a frequency of about 50 GHz, and the periodical structure comprises a period of about a few micrometers (i.e., the period is short compared to the wavelength), the present embodiment provides a higher permittivity epsilon ε_(r) and lower phase velocity speed V_(p) as compared to conventional coplanar waveguide structures. The periodical structure within the signal line 2 essentially provides the ability to have a higher permittivity epsilon and adjust the wavelength. Accordingly, the permittivity epsilon ε_(r) can be varied by different coplanar waveguide structures, such as the various embodiments presented herein. Such higher epsilon coplanar waveguide structures may be incorporated into microwave and millimeter wave integrated circuits, such as circuit impedance matching circuits of the quarter wavelength long transmission line, GPS satellite systems, greater than 2 GHz PDA cell phones, and UWB wireless communication.

The following discussion provides various coplanar waveguide structures that may provide a higher permittivity epsilon ε_(r) and result in an adjusting wavelength. FIG. 2 illustrates a perspective view of one embodiment of a coplanar waveguide structure 10. The coplanar waveguide structure 10 comprises one or more conductor lines 12 a, 12 b, 14 a, 14 b . In the present embodiment, the one or more conductor lines 12 a, 12 b are signal lines (collectively referred to as signal lines 12). The signal lines 12 lie between the one or more conductor lines 14 a, 14 b . The one or more conductor lines 14 a, 14 b are relatively static lines (collectively referred to as relatively static lines 14).

The signal lines 12 may be coupled to a wave source. The wave source may be any suitable frequency. For example, the wave source may include a radio frequency signal source and/or consumer, such as a transmitter, a transceiver, or an antenna. In some embodiments, the signal lines 12 carry a radio frequency signal along their length. In some embodiments, the signal lines may be designed to carry a radio frequency signal in the microwave and/or millimeter range (for example, frequencies between about 300 MHz and about 300 GHz). In the present embodiment, the relatively static lines 14 may be electrically coupled to ground, and thus, the relatively static lines 14 may also be referred to as ground lines. In some embodiments, one or more of the relatively static lines 14 may be coupled to an AC or DC voltage source, including a reference voltage source.

Signal lines 12 are composed of any material capable of propagating a radio frequency signal. Ground lines 14 are composed of any material capable of shielding. For example, the signal lines 12 and/or ground lines 14 may comprise metal, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof. It is understood that the signal lines 12 may comprise the same or different material as the ground lines 14, the signal line 12 a may comprise the same or different material as the signal line 12 b, and the ground line 14 a may comprise the same or different material as the ground line 14 b . Regions between the signal lines 12 and ground lines 14 may be insulating regions, low-k dielectric regions, high-k dielectric regions, other suitable dielectric regions, other suitable regions, and/or combinations thereof. In some embodiments, the regions between the signal lines 12 and the ground lines 14 may comprise a dielectric or other suitable material. In some embodiments, the regions between the signal lines 12 and ground lines 14 may comprise varying materials and/or compositions.

Signal lines 12 and ground lines 14 are oriented substantially parallel to one another in a longitudinal direction. Signal lines 12 and ground lines 14 extend longitudinally a substantially uniform distance L, and signal lines 12/ground lines 14 have a substantially uniform height H. In some embodiments, signal lines 12/ground lines 14 may extend longitudinally varying distances L, and signal lines 12/ground lines 14 may have varying heights H. For example, in some embodiments, the signal lines 12 may extend a first distance, and the ground lines 14 may extend a second distance. In some embodiments, the signal line 12 a may extend a first distance, and signal line 12 b may extend a second distance. The foregoing examples apply equally to the height H for the signal lines 12 and ground lines 14. Further, each signal line 12 a, 12 b is a distance S from a ground line 14 a, 14 b . The distance S may be any suitable distance. Each ground line 14 has a width W_(g). The ground line width W_(g) may be the same or different for each ground line 14. For example, ground lines 14 a, 14 b may be equally wide (i.e., ground line 14 a width W_(g)=ground line 14 b width W_(g)). Ground lines 14 may be wider than they are high (i.e., W_(g)>H), higher than they are wide (i.e., W_(g)<H), square (W_(g)=H), or combinations thereof.

The dimensions of the signal lines 12 vary along a longitudinal axis (in the present embodiment, a z-axis). The variation in dimensions of the signal lines 12 form a periodic structure in the signal lines 12. More specifically, the signal lines 12 include alternating segments, a first segment 16 and a second segment 18, which form the periodic structure. The first segment 16 comprises a width W and a length D_(S). The width W may be the same or different for each signal line 12. For example, the first segments 16 of signal lines 12 a, 12 b may be equally wide (i.e., signal line 12 a width W=signal line 12 b width W). The second segment 18 extends outwardly, horizontally on either side of the signal lines 12 towards ground lines 14, making the second segment 18 wider than the first segment 16. The second segment 18, extending outwardly, may form a rectangular shape, an elliptical shape, a semi-circular shape, a triangular shape, other suitable shape, and/or combinations thereof. In the present embodiment, the second segment 18 forms a rectangular shape having a length D_(L) and a width D_(W). It is understood that the second segment 18 may have different dimensions. It is further understood that, in some embodiments, the second segment 18 may extend inwardly, horizontally on either side of the signal lines 12 towards the center of signal lines 12. In some embodiments, the second segment 18 may extend from only one side of the signal lines 12. In some embodiments, the first segment 16 may be wider than the second segment 18.

The periodic structure in signal line 12, formed by alternating first segments 16 and second segments 18, repeats with a period of D_(S)+D_(L). In other embodiments, the signal line 12 may have a nonperiodic structure, or it may have a structure that includes more or fewer segments. As noted above, the periodic structures in the signal lines 12 provide a higher permittivity epsilon and result in an adjusting wavelength. Accordingly, the dimensions of the coplanar waveguide structure 10 may be selected to provide a desired signal characteristic, for example, a desired phase velocity as described above. In some embodiments, the dimensions W, D_(S), D_(L), and D_(W) may each be between about 0.1 μm and about 8 μm.

The signal lines 12 and ground lines 14 of coplanar waveguide structure 10 may comprise any suitable configuration, wherein the configuration provides a periodic structure. For example, FIGS. 3A-3D and FIGS. 4A-4C illustrate top views of various embodiments of coplanar waveguide structures comprising periodic structures. For example, FIG. 3A illustrates a coplanar waveguide structure 30 comprising signal lines 32 similar to the signal lines 12 described above. The signal lines 32 include alternating segments, first segments 33 and second segments 34. The second segments 34 are wider than the first segments 33 and extend outwardly in a semi-circular shape toward ground lines 35. As noted above, other shapes for first and second segments forming the periodic structure in the signal lines are also possible. For example, FIG. 3B illustrates another embodiment of a coplanar waveguide structure 40 comprising signal lines 42 with first segments 43 and second segments 44. The second segments 44 extend outwardly toward ground lines 45, providing second segments 44 with generally triangular-shaped extensions.

In some embodiments, the ground lines may include a periodic structure or otherwise irregular shaped structure. For example, FIG. 3C illustrates a coplanar waveguide structure 50 comprising signal lines 52 similar to signal lines 12 described above. The signal lines 52 include alternating segments, first segments 53 and second segments 54, that extend outwardly toward ground lines 55 a, 55 b to form rectangular-shaped extensions. The second segments 54 are wider than the first segments 53. The ground lines 55 a, 55 b are substantially uniform in width. The ground lines 55 a, 55 b include a first portion 56 where the distance between the signal lines 52 and the ground lines 55 a, 55 b is relatively small, and a second portion 57 where the distance between the signal lines 52 and the ground lines 55 a, 55 b is relatively large. Although the distance between the signal lines 52 and the ground lines 55 a, 55 b varies, the signal lines 52 and the ground lines 55 a, 55 b are oriented in a same direction and are substantially parallel. FIG. 3C illustrates the first portions of ground lines 55 a, 55 b as coinciding at a longitudinal position along the length of the coplanar waveguide structure 50. The second portions of ground lines 55 a, 55 b are similarly depicted as coinciding. That is, the ground line 55 a is a substantially mirror image of the ground line 55 b reflected across a plane that bisects the signal line lengthwise. However, in other embodiments, the first portion of ground line 55 a may coincide with the second portion of ground line 55 b. That is, the ground line 55 a may be a substantially mirror image of ground line 55 b that has been longitudinally shifted. In still other embodiments, the ground line 55 a may have a form that is unrelated to the form of ground line 55 b. Furthermore, although FIG. 3C illustrates ground lines 55 a, 55 b as having curved sides, the sides of ground lines 55 a, 55 b may also be square, angled, or any other shape or combination of shapes.

In another example, FIG. 3D illustrates a coplanar waveguide structure 60 comprising signal lines 62 similar to signal lines 12 described above. The signal lines 62 include alternating segments, first segments 63 and second segments 64, that extend outwardly toward ground lines 65 to form semi-circular shaped extensions. The second segments 64 are wider than the first segments 63. The ground lines 65 comprise one or more segments 66 that have a substantially similar cross-sectional shape. In the present embodiment, the one or more segments 66 are coupled to one another by an interconnect that may be in the same or a different layer, wherein the interconnect may be a metal interconnect. The one or more segments may comprise any suitable material. For example, in some embodiments, the segments 66 may comprise two or more different materials, such as one or more of the segments 66 comprising a conductive material and one or more of the segments 66 comprising nonconductive material. In some embodiments, the segments may be composed of the same material as the signal lines 62.

It is understood that various aspects of the coplanar waveguide structures disclosed herein may be combined in a single coplanar waveguide structure. For example, FIGS. 4A-4C show coplanar waveguide structures 70, 80, 90 comprising one or more signal lines 72, 82, 92 and one or more ground lines 75, 85, 95 having periodic structures similar to the signal lines and ground lines described above. Referring to FIG. 4A, the signal lines 72 include alternating segments, first segments 73 and second segments 74. The second segments 74 are wider than the first segments 73 and extend outwardly in a semi-circular shape toward ground lines 75. The ground lines 75 also include alternating segments, first segments 76 and second segments 77. The second segments 77 are wider than the first segments 76 and similarly extend outwardly in a semi-circular shape. Referring to FIG. 4B, the signal lines 82 and the ground lines 85 comprise alternating segments, first segments 83, 86 and second segments 84, 87. The second segments 84, 87 are wider than the first segments 83, 86 and extend outwardly in a triangular shape. Referring to FIG. 4C, the signal lines 92 and the ground lines 95 comprise alternating segments, first segments 93, 96 and second segments 94, 97. The second segments 94, 97 are wider than the first segments 93, 96. The second segments 94 of the signal lines 92 extend outwardly in a semi-circular shape, and the second segments 97 of the ground lines 95 extend outwardly in a triangular shape.

Referring now to FIGS. 5A-5D, a transverse cross-sectional view of a device 100 including a coplanar waveguide structure according to one embodiment is illustrated. The device 100 includes a lower substrate 102 and an upper substrate 104 including one or more low-k dielectric layers 106 and coplanar waveguide portions 108.

The lower substrate 102 may comprise any suitable material and any suitable thickness. In the present embodiment, the lower substrate 102 comprises a semiconductor substrate, such as a silicon substrate. The lower substrate 102 may comprise an elementary semiconductor including silicon or germanium in crystal, polycrystalline, or an amorphous structure; a compound semiconductor including silicon carbide, gallium arsenic, gallium phosphide, indium phosphide, indium arsenide, and indium antimonide; an alloy semiconductor including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and GaInAsP; any other suitable material; and/or combinations thereof. In one embodiment, the alloy semiconductor substrate may have a gradient SiGe feature in which the Si and Ge composition change from one ratio at one location to another ratio at another location of the gradient SiGe feature. In another embodiment, the alloy SiGe is formed over a silicon substrate. In another embodiment, a SiGe substrate is strained. Furthermore, the substrate may be a semiconductor on insulator (SOI) or a thin film transistor (TFT). In some examples, the semiconductor substrate may include a doped epi layer or a buried layer. In other examples, the compound semiconductor substrate may have a multilayer structure, or the silicon substrate may include a multilayer compound semiconductor structure. In some embodiments, the lower substrate 102 may comprise glass.

The lower substrate 102 may include multiple layers comprising the same or varying materials. The lower substrate 102 may further include various doping configurations depending on design requirements as known in the art (e.g., p-type substrate regions or n-type substrate regions). In some embodiments, the lower substrate 102 may include doped regions. It is understood that the lower substrate 102 may comprise partially or fully fabricated devices, structures, and or features known in the art, including but not limited to gate structures, source/drain regions, lightly doped regions, shallow trench isolations, transistors, diodes, vias, trenches, various contacts/vias and multilayer interconnect features (e.g., metal layers and interlayer dielectrics), other features, and/or combinations thereof.

The upper substrate 104 may comprise any suitable material and any suitable thickness. The upper substrate 104 may comprise one or more insulating layers. In the present embodiment, the upper substrate 104 comprises a dielectric material, such as TEOS oxide, silicon oxide, silicon nitride, silicon oxynitride, hafnium oxide, zirconium oxide, titanium oxide, aluminum oxide, hafnium dioxide-alumina (HfO₂—Al₂O₃) alloy, PSG, BPSG, other suitable dielectric materials, and/or combinations thereof. In some embodiments, the upper substrate 104 may comprise a high-k dielectric material, which may include metal oxides, metal nitrides, metal silicates, transition metal-oxides, transition metal-nitrides, transition metal-silicates, oxynitrides of metals, metal aluminates, zirconium silicate, zirconium aluminate, HfO₂, HfSiO, HfSiON, HfTaO, HfTaTiO, HfTiO, HfZrO, HfAlON, other suitable high-k dielectric materials, and/or combinations thereof. In some embodiments, the upper substrate may comprise a low-k dielectric material, such as fluorinated silica glass (FSG), carbon doped silicon oxide, Black Diamond® (Applied Materials of Santa Clara, Calif.), Xerogel, Aerogel, amorphous fluorinated carbon, Parylene, BCB (bis-benzocyclobutenes), SiLK (Dow Chemical, Midland, Mich.), polyimide, other proper porous polymeric materials, and/or combinations thereof.

It is understood that the upper substrate 104 may include a multilayer structure, wherein each layer comprises the same or varying materials, such as varying dielectric and metal materials. It is further understood that additional layers may be formed overlying and/or underlying the upper substrate 104. In the present embodiment, the upper substrate 104 includes the one or more low-k dielectric layers 106 and coplanar waveguide portions 108. The one or more low-k dielectric layers 106 may comprise any suitable dielectric material, such as the materials described above and/or dielectric materials with a dielectric constant of less than about 3.9. The one or more low-k dielectric layers 106 may comprise any suitable thickness. The one or may low-k dielectric layers 106 and coplanar waveguide portions 108 may be included at any suitable location in the upper substrate 104. For example, the low-k dielectric layer 106 may be formed below the coplanar waveguide portions 108 as illustrated in FIG. 5A, the low-k dielectric layer 106 may be formed above the coplanar waveguide portions 108 as illustrated in FIG. 5B; one or more low-k dielectric layers 106 may be formed above and below the coplanar waveguide portions 108 as illustrated in FIG. 5C; or the coplanar waveguide portions 108 may be formed in the low-k dielectric layer 106 as illustrated in FIG. 5D. Similarly, the coplanar waveguide portions 108 may be included at locations other than those illustrated, and such locations are not limited by FIGS. 5A-5D.

The coplanar waveguide portions 108 collectively form a coplanar waveguide structure. The coplanar waveguide structure may be similar to the coplanar waveguide structures described herein. For example, the coplanar waveguide portions 108 may comprise signal lines and ground lines. In the present embodiment, portions of the upper substrate 104 lie between the coplanar waveguide portions 108; however, it is understood that, in alternate embodiments, other suitable regions may lie between the coplanar waveguide portions, such as insulating regions, low-k dielectric regions, high-k dielectric regions, other suitable dielectric regions, other suitable regions, and/or combinations thereof. The coplanar waveguide portions 108 may comprise any suitable material and any suitable thickness. For example, the coplanar waveguide portions 108 may comprise a metal, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof.

FIGS. 6A-6C show perspective views of various embodiments of a coplanar waveguide structure 200, wherein the coplanar waveguide structure 200 includes one or more islands. Introducing the one or more islands into the coplanar waveguide structure 200 increases the permittivity epsilon and results in an adjusting wavelength. The coplanar waveguide structure 200 comprises one or more signal lines 202, one or more ground lines 204, and one or more islands 206. The signal lines 202 and ground lines 204 are similar to the signal lines and ground lines discussed above. Particularly, the signal lines 202 comprise a periodic structure comprising first segments 203 a and second segments 203 b, the second segments 203 a forming rectangular-shaped extensions. However, it is understood that the signal lines 202 may comprise any suitable periodic structure, and each of the signal lines 202 may comprise the same periodic structure, varying periodic structures, or no periodic structure. Referring to FIG. 6A, signal lines 202 are disposed between ground lines 204, and one or more islands 206 are disposed between each of the signal lines 202 and each of the ground lines 204. The islands 206 coincide with the second segments 203 b of the periodic structure in signal lines 202. That is, the coplanar waveguide structure 200 has islands 206 at periodic intervals along its length, the signal lines 202 have second segments 203 b at periodic intervals along its length (as discussed in further detail above), and the period of the islands 206 is equal to the period of the second segments 203 b of the periodic structure in signal lines 202. In some embodiments, the islands 206 may coincide with the first segments 203 a of the periodic structure in signal lines 202. In still other embodiments, the islands 206 may be at intervals that do not correspond to the periodic structure of the signal lines 202. FIG. 6B is similar to FIG. 6A and additionally includes one or more islands 206 disposed between the signal lines 202 at periodic intervals along the length of the coplanar waveguide structure 200. FIG. 6C is similar to FIG. 6A and additionally includes one or more ground lines 204 disposed between the signal lines 202. It is understood that the coplanar waveguide structure 200 is not limited by FIGS. 6A-6C and may comprise any combination and configuration of signal lines 202, ground lines 204, and islands 206.

The one or more of the islands 206 may be electrically intercoupled and/or electrically isolated from one another; electrically coupled to one or more of the signal lines 202, one or more of the ground lines 204, and/or a reference voltage or signal; completely electrically isolated; and/or combinations thereof. Where one or more islands 206 are electrically coupled, the electrical coupling may be through an interconnect or via. Further, the signal lines 202, ground lines 204, and islands 206 may be any suitable distance from one another. For example, the islands 206 may be closer to the signal lines 202 than to the ground lines 204, closer to the ground lines 204 than to the signal lines 202, or equidistant to the nearest signal line 202 and the nearest ground line 206. In some embodiments, some islands 206 may be closer to the signal lines 202 than some other islands 206. That is, the distance between the signal lines 202 and the islands 206 may vary over the length of the coplanar waveguide structure 200.

In the present embodiment, the islands 206 may be referred to as conductive pillars. The islands 206 may comprise any suitable shape, such as a rectangular shape, a circular shape, an elliptical shape, a triangular shape, other suitable shape, and/or combinations thereof. In some embodiments, the islands 206 comprise quadrilateral frusta, rectangular prisms, elliptic cylinders, circular cylinders, or combinations thereof. Further, the islands 206 may be substantially uniform in form and dimension, or the islands 206 may vary in form, dimension, or both. The islands 206 may have a uniform composition or a varied composition. The islands 206 may comprise any material, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof. In other embodiments, some or all of the islands 206 may comprise a dielectric material. It is understood that each of the one or more islands 206 may comprise the same material or different materials. Further, the islands 206 may be composed of the same or a different material as the signal lines 202 and/or ground lines 204. In some embodiments, all the islands 206 are composed of the same material as the signal lines 202.

FIGS. 7A-7D show perspective views of various embodiments of a coplanar waveguide structure 300, wherein the coplanar waveguide structure 300 includes one or more floating strips above and/or beneath the signal lines/ground lines including periodic structures. Combining the one or more floating strips with the one or more signal lines/ground lines having periodic structures increases the permittivity epsilon and results in an adjustable wavelength. The coplanar waveguide structure 300 includes a first layer comprising one or more signal lines 302 and one or more ground lines 304 and a second layer comprising one or more floating strips 308. The signal lines 302 and ground lines 304 are similar to the signal lines 12 and ground lines 14 previously described with respect to FIG. 2. Particularly, at least one of the one or more signal lines 302 includes a periodic structure. In some embodiments, at least one of the one or more ground lines 304 includes a periodic structure. The first layer may be separated from the second layer by a dielectric layer or other suitable material. The second layer comprising the one or more floating strips 308 may be located below the first layer comprising the signal lines 302/ground lines 304 as illustrated in FIGS. 7A, 7B or above the first layer comprising the signal lines 302/ground lines 304 as illustrated in FIGS. 7C, 7D. In some embodiments, the coplanar waveguide structure 300 may include two second layers comprising one or more floating strips 308, one located above the first layer and the other located below the first layer. In some embodiments, the coplanar waveguide structure 300 may include multiple second layers comprising one or more floating strips 308 above and/or below the first layer. Regions between the various layers and features of the coplanar waveguide structures may be insulating regions, low-k dielectric regions, high-k dielectric regions, other suitable dielectric regions, other suitable regions, and/or combinations thereof. In some embodiments, the regions between the various layers and features may comprise varying materials and/or compositions.

The floating strips 308 may extend across substantially the entire width of the coplanar waveguide structure 300 or a portion of the width of the coplanar waveguide structure 300. Further, the floating strips 308 may be at periodic intervals along the length of the coplanar waveguide structure 300. If at such periodic intervals, the floating strips 308 may disposed at any suitable period. The floating strips 308 may comprise any suitable material. In the present embodiment, the floating strips 308 comprise a conductive material, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof. In some embodiments, the floating strips 308 may comprise one or more layers. In some embodiments, the floating strips 308 may be similar to the conductive strips described in U.S. Pat. No. 7,242,272, entitled “Methods and Apparatus Based on Coplanar Striplines,” issued to Ham et al. and/or U.S. Pat. No. 6,950,590, entitled “Transmission Lines and Components with Wavelength Reduction and Shielding,” issued to Cheung et al., both of which are hereby incorporated by reference. Further, the one or more of the floating strips 308 may be electrically intercoupled and/or electrically isolated from one another; electrically coupled to one or more of the signal lines 302, one or more of the ground lines 304, and/or a reference voltage or signal; completely electrically isolated; and/or combinations thereof. Where one or more floating strips are electrically coupled, the electrical coupling may be through an interconnect or via.

FIGS. 8A-8F show perspective views of various embodiments of a coplanar waveguide structure 400, wherein the coplanar waveguide structure 400 includes one or more floating strips above and/or beneath the signal lines/ground lines including periodic structures and the islands. Combining the one or more floating strips with the one or more signal lines having periodic structures and the islands increases the permittivity epsilon and results in an adjustable wavelength. The coplanar waveguide structure 400 includes a first layer comprising one or more signal lines 402, one or more ground lines 404, and one or more islands 406 and a second layer comprising one or more floating strips 408. The signal lines 402, ground lines 404, islands 406, and floating strips 408 are similar to the signal lines, ground lines, islands, and floating strips previously described with respect to the various embodiments above. Particularly, at least one of the one or more signal lines 402 includes a periodic structure. In some embodiments, at least one of the one or more ground lines 404 includes a periodic structure. The islands 406 and floating strips 408 may be at periodic intervals along the coplanar waveguide structure 400, and the period of the floating strips 408 may be the same as or different than the period of the islands 406. The first layer is separated from the second layer by a dielectric layer. The second layer comprising the one or more floating strips 408 may be located below the first layer comprising the signal lines 402/ground lines 404/islands 406 as illustrated in FIGS. 8A, 8B, 8C or above the first layer comprising the signal lines 402/ground lines 404/islands 406 as illustrated in FIGS. 8D, 8E, 8F. In some embodiments, the coplanar waveguide structure 400 may include two second layers comprising one or more floating strips 408, one located above the first layer and the other located below the first layer. In some embodiments, the coplanar waveguide structure 400 may include multiple second layers comprising one or more floating strips 408 above and/or below the first layer. Regions between the various layers and features of the coplanar waveguide structure may be insulating regions, low-k dielectric regions, high-k dielectric regions, other suitable dielectric regions, other suitable regions, and/or combinations thereof. In some embodiments, the regions between the various layers and features may comprise varying materials and/or compositions.

FIGS. 9A-9D show perspective views of various embodiments of a coplanar waveguide structure 500, wherein the coplanar waveguide structure 500 includes one or more signal lines, one or more ground lines, and one or more islands. The coplanar waveguide structure 500 comprises one or more signal lines 502, one or more ground lines 504, and one or more islands 506. The ground signal lines 502, ground lines 504, and islands 506 are similar to the signal lines, ground lines, and islands previously described with respect to the various embodiments above. In FIGS. 9A-9D, the signal lines 502 and ground lines 504 do not include a periodic structure, illustrating that introducing the islands 506 alone into the coplanar waveguide structure 500 increases the permittivity epsilon and results in an adjustable wavelength. The islands 506 may be disposed at periodic intervals. Referring to FIG. 9A, signal lines 502 are disposed between ground lines 504, and one or more islands 506 are disposed between each of the signal lines 502 and each of the ground lines 504. FIG. 9B is similar to FIG. 9A and additionally includes one or more islands 506 disposed between the signal lines 502. FIG. 9C is similar to FIG. 9A and additionally includes one or more ground lines 504 disposed between the signal lines 502. FIG. 9D is similar to FIG. 9A and includes one or more islands 506 disposed on either side of each signal line 502 and each ground line 504. It is understood that the coplanar waveguide structure 500 is not limited by FIGS. 9A-9D and may comprise any combination and configuration of signal lines 502, ground lines 504, and islands 506.

FIGS. 10A-10F show perspective views of various embodiments of a coplanar waveguide structure 600, wherein the coplanar waveguide structure 600 includes one or more floating strips above and/or beneath the signal lines/ground lines and the islands. Combining the one or more floating strips with the one or more signal lines, even absent having periodic structures, and the islands increases the permittivity epsilon and results in an adjustable wavelength. The coplanar waveguide structure 600 includes a first layer comprising one or more signal lines 602, one or more ground lines 604, and one or more islands 606 and a second layer comprising one or more floating strips 608. The signal lines 602, ground lines 604, islands 606, and floating strips 608 are similar to the signal lines, ground lines, islands, and floating strips previously described with respect to the various embodiments above. Particularly, the islands 606 and floating strips 608 may be at periodic intervals along the length of the coplanar waveguide 600, and the period of the floating strips 608 may be the same as or different than the period of the islands 606. The first layer is separated from the second layer by a dielectric layer. The second layer comprising the one or more floating strips 608 may be located below the first layer comprising the signal lines 602/ground lines 604/islands 606 as illustrated in FIGS. 10A, 10B, 10C or above the first layer comprising the signal lines 602/ground lines 604/islands 606 as illustrated in FIGS. 10D, 10E, 10F. In some embodiments, the coplanar waveguide structure 600 may include two second layers comprising one or more floating strips 608, one located above the first layer and the other located below the first layer. In some embodiments, the coplanar waveguide structure 600 may include multiple second layers comprising one or more floating strips 608 above and/or below the first layer.

In some embodiments, as further detailed below, a reduced wavelength characteristic is achieved in transmission lines by adding periodical shielding structures (e.g., metal strip shields) in the coplanar waveguide structures. The periodical shielding structures may result in decelerating the propagation speed. Such decelerated propagation speed in a guided medium is called a slow-wave. Increasing the slow wave feature and reducing the electric filed coupled to a substrate of a device may also be achieved. Accordingly, the below embodiments, comprising coplanar waveguide structures combined with a variety of different shielding structures may be referred to as slow-wave coplanar waveguide (CPW) transmission lines. The slow-wave CPW transmission lines may increase the relative permittivity and simultaneously reduce attenuation loss.

Further, in some embodiments, the ground signals may be eventually replaced with floating shielding structures, such as those described below, particularly in high frequency devices. An AC source causes the polarity of the ground potential to alternate between positive and negative over the complete RF cycle, resulting in energy being coupled to a conductive substrate. Since shielding structures in the present embodiments may be adequate conductors, and may also be isolated, there is no net charge on the shielding structures. Thus, no electromagnetic flux exists below the shielding structures, and the shielding structures are immune to both positive and negative potential swings, which allows energy coupled to a substrate to be minimized. Consequently, the shielding structures may essentially replace a ground connection in some embodiments.

Referring to FIG. 11, a transverse cross-sectional view of a device 700 including a lower substrate 702, an upper substrate 704, a coplanar waveguide structure 706 including one or more conductor lines 707 a, 707 b, and a shielding structure 708 including one or more slot-type floating strips 709 is provided.

The lower substrate 702 may comprise any suitable material and any suitable thickness. In the present embodiment, the lower substrate 702 comprises a semiconductor substrate, such as a silicon substrate. The lower substrate 702 may comprise an elementary semiconductor including silicon or germanium in crystal, polycrystalline, or an amorphous structure; a compound semiconductor including silicon carbide, gallium arsenic, gallium phosphide, indium phosphide, indium arsenide, and indium antimonide; an alloy semiconductor including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and GaInAsP; any other suitable material; and/or combinations thereof. In one embodiment, the alloy semiconductor substrate may have a gradient SiGe feature in which the Si and Ge composition change from one ratio at one location to another ratio at another location of the gradient SiGe feature. In another embodiment, the alloy SiGe is formed over a silicon substrate. In another embodiment, a SiGe substrate is strained. Furthermore, the substrate may be a semiconductor on insulator (SOI) or a thin film transistor (TFT). In some examples, the semiconductor substrate may include a doped epi layer or a buried layer. In other examples, the compound semiconductor substrate may have a multilayer structure, or the silicon substrate may include a multilayer compound semiconductor structure. In some embodiments, the lower substrate 702 may comprise glass.

The lower substrate 702 may further include multiple layers comprising the same or varying materials. The lower substrate 702 may include various doping configurations depending on design requirements as known in the art (e.g., p-type substrate regions or n-type substrate regions). In some embodiments, the lower substrate 702 may include doped regions. It is understood that the lower substrate 702 may comprise partially or fully fabricated devices, structures, and or features known in the art, including but not limited to gate structures, source/drain regions, lightly doped regions, shallow trench isolations, transistors, diodes, vias, trenches, various contacts/vias and multilayer interconnect features (e.g., metal layers and interlayer dielectrics), other features, and/or combinations thereof.

The upper substrate 704 is formed over the lower substrate 702. The upper substrate 704 may comprise any suitable material and any suitable thickness. In the present embodiment, the upper substrate 104 comprises a dielectric material, such as TEOS oxide, silicon oxide, silicon nitride, silicon oxynitride, hafnium oxide, zirconium oxide, titanium oxide, aluminum oxide, hafnium dioxide-alumina (HfO₂—Al₂O₃) alloy, PSG, BPSG, other suitable dielectric materials, and/or combinations thereof. In some embodiments, the upper substrate 704 may comprise a high-k dielectric material, which may include metal oxides, metal nitrides, metal silicates, transition metal-oxides, transition metal-nitrides, transition metal-silicates, oxynitrides of metals, metal aluminates, zirconium silicate, zirconium aluminate, HfO₂, HfSiO, HfSiON, HfTaO, HfTaTiO, HfTiO, HfZrO, HfAlON, other suitable high-k dielectric materials, and/or combinations thereof. In some embodiments, the upper substrate 704 may comprise a low-k dielectric material, such as fluorinated silica glass (FSG), carbon doped silicon oxide, Black Diamond® (Applied Materials of Santa Clara, Calif.), Xerogel, Aerogel, amorphous fluorinated carbon, Parylene, BCB (bis-benzocyclobutenes), SiLK (Dow Chemical, Midland, Mich.), polyimide, other proper porous polymeric materials, and/or combinations thereof. It is understood that the upper substrate 104 may include a multilayer structure, wherein each layer comprises the same or varying materials, such as varying dielectric and metal materials. It is further understood that additional layers may be formed overlying and/or underlying the upper substrate 704.

The coplanar waveguide structure 706 and the shielding structure 708 may be formed above, below, and/or within upper substrate 704. The coplanar waveguide structure 706 comprises the one or more conductor lines 707 a, 707 b. The one or more conductor lines 707 a, 707 b are similar to the conductor lines, signal lines, and ground lines described herein. For example, the one or more conductor lines 707 a comprise signal lines and the one or more conductor lines 707 b comprise ground lines. Similar to the signal lines/ground lines described above, in some embodiments, at least one of the one or more conductor lines 707 a and/or ground lines 707 b may include a periodic structure. Further, the signal lines 707 a/ground lines 707 b may comprise any suitable material and any suitable thickness. For example, the signal lines 707 a/ground lines 707 b may comprise a metal, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof. In some embodiments, the signal lines 707 a/ground lines 707 b may comprise the same material or varying materials. Regions between the one or more conductor lines 707 a, 707 b may be portions of the upper substrate 704, insulating regions, low-k dielectric regions, high-k dielectric regions, other suitable dielectric regions, other suitable regions, and/or combinations thereof.

In the present embodiment, the shielding structure 708 including the one or more slot-type floating strips 709 is formed above the coplanar waveguide structure 706. In some embodiments, the shielding structure 708 may include the one or more slot-type floating strips 709 formed below the coplanar waveguide structure 706. The slot-type floating strips 709 may extend transversely to the coplanar waveguide structure 706 and may further extend across substantially the entire width of the coplanar waveguide structure 706 or a portion of the width of the coplanar waveguide structure 706. The slot-type floating strips 709 are similar to the floating strips described above, comprising a strip length S_(L), which may be any suitable length. The slot-type floating strips are spaced apart at any suitable distance S_(S). In some embodiments, each of the slot-type floating strips may be spaced apart equal distances and/or varying distances. The slot-type floating strips 709 may be at periodic intervals along the length of the coplanar waveguide structure 706. If at such periodic intervals, the slot-type floating strips 709 may disposed at any suitable period. The slot-type floating strips 709 comprise any suitable material. For example, the slot-type floating strips 709 may comprise a conductive material, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof. In some embodiments, each of the one or more slot-type floating strips 709 may comprise the same material or varying materials. Further, the one or more slot-type floating strips 709 may be electrically intercoupled and/or electrically isolated from one another; electrically coupled to one or more of the conductor lines 707 a, 707 b, and/or a reference voltage or signal; completely electrically isolated; and/or combinations thereof. Where one or more slot-type floating strips 709 are electrically coupled, the electrical coupling may be through an interconnect or via. Regions between the slot-type floating strips 709 and regions between the coplanar waveguide structure 706 and the shielding structure 708 may be portions of the upper substrate 704, insulating regions, low-k dielectric regions, high-k dielectric regions, other suitable dielectric regions, other suitable regions, and/or combinations thereof.

Referring to FIG. 12, a transverse cross-sectional view of a device 800 including a lower substrate 802, an upper substrate 804, a coplanar waveguide structure 806 including one or more conductor lines 807 a, 807 b, and a shielding structure including a first portion 808 a and a second portion 808 b (collectively referred to as a shielding structure 808), the first and second portions 808 a, 808 b comprising one or more slot-type floating strips 809 a, 809 b, is provided. The lower substrate 802, upper substrate 804, coplanar waveguide structure 806 including one or more conductor lines 807 a, 807 b are similar to the lower substrate, upper substrate, and coplanar waveguide structure including one or more conductor lines described above with reference to FIG. 11. However, in the present embodiment, the shielding structure 808 includes the first portion 808 a comprising one or more slot-type floating strips 809 a formed above the coplanar waveguide structure 806 and the second portion 808 b comprising one or more slot-type floating strips 809 b formed above the coplanar waveguide structure 806. The slot-type floating strips 809 a, 809 b are similar to the slot-type floating strips 709 described in FIG. 11. The slot-type floating strips 809 a, 809 b extend transversely to the coplanar waveguide structure 806 and may further extend across substantially the entire width of the coplanar waveguide structure 806 or a portion of the width of the coplanar waveguide structure 806. The slot-type floating strips 809 a, 809 b are spaced apart at any suitable distance. In some embodiments, each of the slot-type floating strips may be spaced apart equal distances and/or varying distances. The slot-type floating strips 809 a, 809 b may be at periodic intervals along the length of the coplanar waveguide structure 806. If at such periodic intervals, the slot-type floating strips 809 a, 809 b may disposed at any suitable period. It is understood that the first portion 808 a comprising one or more slot-type floating strips 809 a and the second portion 808 b comprising one or more slot-type floating strips 809 b may be the same or different in form, substance, and/or dimension. For example, the first portion 808 a may include the slot-type floating strips 809 a comprising a first material and/or placed at a first periodical interval; and the second portion 808 b may include the slot-type floating strips 809 b comprising a second material and/or placed at a second periodical interval.

FIGS. 13 and 14 provide transverse cross-sectional views of devices 900 and 1000 comprising shielding structures including one or more slot-type floating strips having extensions. Device 900 comprises a lower substrate 902, an upper substrate 904, a coplanar waveguide structure 906 including one or more conductor lines 907 a, 907 b, and a shielding structure 908 including one or more slot-type floating strips 909 having one or more extensions. Device 1000 comprises a lower substrate 1002, an upper substrate 1004, a coplanar waveguide structure 1006 including one or more conductor lines 1007 a, 1007 b, and a shielding structure 1008 including one or more slot-type floating strips 1009 having one or more extensions. The lower substrates 902, 1002; upper substrates 904, 1004; and coplanar waveguide structures 906, 1006 including one or more conductor lines 907 a, 907 b, 1007 a, 1007 b are similar to the lower substrates, upper substrates, and coplanar waveguide structures including one or more conductor lines described above.

The shielding structures 908, 1008 including one or more slot-type floating strips 909, 1009 are also similar to the shielding structures described above, except the shielding structures 908, 1008 include one or more slot-type floating strips 909, 1009 having extensions. It is understood that the extensions may be an integral part of the slot-type floating strips 909, 1009, or in some embodiments, the extensions may be separate features of the shielding structures 908, 1008, coupled (and/or connected) to the slot-type floating strips 909, 1009. Referring to FIG. 13, the shielding structure 909 is formed below the coplanar waveguide structure 906, and the slot-type floating strips 909 also include a portion that extends from below the coplanar waveguide structure 906 to above (or even with) the coplanar waveguide structure 906 (i.e., extends upwardly away from the lower substrate 902 and upper substrate 904). Referring to FIG. 14, the shielding structure 1008 is formed above the coplanar waveguide structure 1006, and the slot-type floating strips 1009 include a portion that extends from above the coplanar waveguide structure 1006 to below (or even with) the coplanar waveguide structure 1006 (i.e., extends downwardly toward the lower substrate 1002 and upper substrate 1004). The portions of the slot-type floating strips 909, 1009 may extend partially or entirely along the height of the coplanar waveguide structures 906, 1006. In the present embodiments, the portion of the slot-type floating strips 909, 1009 that extends vertically forms a rectangular-shaped extension. It is contemplated that the slot-type floating strips 909, 1009 may include other shaped extensions, such as circular-shaped, elliptical-shaped, triangular-shaped, other suitable shapes, and/or combinations thereof.

FIG. 15 provides a transverse cross-sectional view of device 1100 comprising a lower substrate 1102, an upper substrate 1104, a coplanar waveguide structure 1106 including one or more conductor lines 1107 a, 1107 b, and a shielding structure 1108 including one or more slot-type floating shields 1109. The lower substrate 1102, upper substrate 1104, and coplanar waveguide structure 1106 including one or more conductor lines 1107 a, 1107 b are similar to the lower substrates, upper substrates, and coplanar waveguide structures including one or more conductor lines described above. In the present embodiment, the slot-type floating shields 1109 are rectangular-shaped, surrounding the coplanar waveguide structure 1106. It is understood that the slot-type floating shields 1109 may comprise any suitable shape, for example, surrounding the coplanar waveguide with circular-shaped slot-type floating shields. The slot-type floating shields 1109 may be spaced at periodic intervals at any suitable period along the length of the coplanar waveguide structure 1106. Additionally, the slot-type floating shields 1109 may be similar in various respects to the slot-type floating strips and slot-type floating strips having extension described above. Further, the one or more slot-type floating shields 1109 may be electrically intercoupled and/or electrically isolated from one another; electrically coupled to one or more of the conductor lines 1107 a, 1107 b, and/or a reference voltage or signal; completely electrically isolated; and/or combinations thereof. Where one or more slot-type floating shields 1109 are electrically coupled, the electrical coupling may be through an interconnect or via.

FIGS. 16, 17, and 18 provide transverse cross-sectional views of devices 1200, 1300, and 1400 comprising shielding structures according to various embodiments. Device 1200 comprises a lower substrate 1202, an upper substrate 1204, a coplanar waveguide structure 1206 including one or more conductor lines 1207 a, 1207 b, and a shielding structure 1208 including one or more slot-type floating strips 1209 and one or more slot-type grounded strips 1210. Device 1300 comprises a lower substrate 1302, an upper substrate 1304, a coplanar waveguide structure 1306 including one or more conductor lines 1307 a, 1307 b, and a shielding structure 1308 including one or more slot-type floating strips 1309 and one or more slot-type grounded strips 1310. Device 1400 comprises a lower substrate 1402, an upper substrate 1404, a coplanar waveguide structure 1406 including one or more conductor lines 1407 a, 1407 b, and a shielding structure comprising a first portion 1408 a and a second portion 1408 b (collectively referred to as shielding structure 1408), wherein the first and second portions 1408 a, 1408 b include one or more slot-type floating strips 1409 and one or more slot-type grounded strips 1410. The lower substrates 1202, 1302, 1402; upper substrates 1204, 1304, 1404; and coplanar waveguide structures 1206, 1306, 1406 including one or more conductor lines 1207 a, 1207 b, 1307 a, 1307 b, 1407 a, 1407 b are similar to the lower substrates, upper substrates, and coplanar waveguide structures including one or more conductor lines described above.

The shielding structures 1208, 1308, 1408 are similar to the shielding structures described above, particularly, the slot-type floating strips 1209, 1309, 1409 are similar to the slot-type floating strips described above. However, in the present embodiments, the shielding structures 1208, 1308, 1408 include one or more slot-type grounded strips 1210, 1310, 1410 coupled to (and/or connected to) the slot-type floating strips 1209, 1309, 1409. For example, referring to FIG. 16, the shielding structure 1209 is formed above the coplanar waveguide structure 1206, and the slot-type floating strips 1209 are coupled to one or more slot-type grounded strips 1210. Referring to FIG. 17, the shielding structure 1308 is formed below the coplanar waveguide structure 1306, and the slot-type floating strips 1309 are coupled to one or more slot-type grounded strips 1310. Referring to FIG. 18, the shielding structure 1408 comprises a first portion 1408 a formed above the coplanar waveguide structure 1406 and a second portion 1408 b formed below the coplanar waveguide structure 1406, and the slot-type floating strips 1409 are coupled to one or more slot-type grounded strips 1410.

The one or more slot-type grounded strips 1210, 1310, 1410 may extend partially or entirely along the length of the coplanar waveguide structures 1206, 1306, 1406. The slot-type grounded strips 1210, 1310, 1410 are substantially uniform in length, height, and width, and further lie substantially parallel with respect to one another. It is understood that, in alternate embodiments, the slot-type grounded strips 1210, 1310, 1410 may comprise varying lengths, heights, and/or widths. In the present embodiments, the shielding structures comprise two substantially identical parallel slot-type grounded strips 1210, 1310, 1410 coupled to the slot-type floating strips 1209. The slot-type grounded strips 1210, 1310, 1410 may be similar to the slot-type floating strips 1209. The slot-type grounded strips 1210, 1310, 1410 comprise any suitable material, for example, a conductive material, such as aluminum, copper, tungsten, titanium, tantulum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, silver, TaC, TaSiN, TaCN, TiAl, TiAlN, metal alloys, other suitable materials, and/or combinations thereof. In some embodiments, each of the one or more slot-type grounded strips 1210, 1310, 1410 may comprise the same material or varying materials. Regions between the slot-type grounded strips 1210, 1310, 1410 and/or the slot-type floating strips 1208, 1308, 1408 and regions between the coplanar waveguide structures 1206, 1306, 1406 and the shielding structures 1208, 1308, 1408 may be portions of the upper substrates 1204, 1304, 1404, insulating regions, low-k dielectric regions, high-k dielectric regions, other suitable dielectric regions, other suitable regions, and/or combinations thereof.

The slot-type grounded strips 1210, 1310, 1410 are at any suitable position. Adjusting the position of the slot-type grounded strips 1210, 1310, 1410 allows the characteristic impedance of the devices 1200, 1300, 1400 to be varied and tuned as desired. Where high performance requirements are desired, such as in high quality stub inductors, impedance matching networks of a quarter-wavelength-long transmission line, resonators, oscillators, signal splitters, combiners, amplifiers, and filters, the tunable characteristic impedance provided is highly desirable. In some embodiments, each of the slot-type grounded strips 1210, 1310, 1410 may be spaced apart equal distances and/or varying distances. In some embodiments, the slot-type grounded strips 1210, 1310, 1410 may be at periodic intervals along the width of the coplanar waveguide structures 1206, 1306, 1406 at any suitable period. Further, the one or more slot-type grounded strips 1210, 1310, 1410 may be electrically intercoupled and/or electrically isolated from one another; electrically coupled to one or more of the conductor lines 1207 a, 1207 b, 1307 a, 1307 b, 1407 a, 1407 b, and/or a reference voltage or signal; completely electrically isolated; and/or combinations thereof. Where one or more slot-type grounded strips 1210, 1310, 1410 are electrically coupled, the electrical coupling may be through an interconnect or via.

FIGS. 19, 20, and 21 provide transverse cross-sectional views of devices 1500, 1600, and 1700 comprising shielding structures according to various embodiments. Device 1500 comprises a lower substrate 1502, an upper substrate 1504, a coplanar waveguide structure 1506 including one or more conductor lines 1507 a, 1507 b, and a shielding structure 1508 including one or more slot-type floating strips 1509, one or more slot-type grounded strips 1510, and one or more extensions 1512. Device 1600 comprises a lower substrate 1602, an upper substrate 1604, a coplanar waveguide structure 1606 including one or more conductor lines 1607 a, 1607 b, and a shielding structure 1608 including one or more slot-type floating strips 1609, one or more slot-type grounded strips 1610, and one or more extensions 1612. Device 1700 comprises a lower substrate 1702, an upper substrate 1704, a coplanar waveguide structure 1706 including one or more conductor lines 1707 a, 1707 b, a shielding structure comprising a first portion 1708 a and a second portion 1708 b (collectively referred to as shielding structure 1708), wherein the first and second portions 1708 a, 1708 b include one or more slot-type floating strips 1709, one or more slot-type grounded strips 1710, and extensions 1712. The lower substrates 1502, 1602, 1702; upper substrates 1504, 1604, 1704; and coplanar waveguide structures 1506, 1606, 1706 including one or more conductor lines 1507 a, 1507 b, 1607 a, 1607 b, 1707 a, 1707 b are similar to the lower substrates, upper substrates, and coplanar waveguide structures including one or more conductor lines described above.

The shielding structures 1508, 1608, 1708 including the slot-type floating strips 1509, 1609, 1709 and slot-type grounding strips 1510, 1610, 1710 are also similar to the shielding structures including slot-type floating strips and/or slot-type grounding strips described above, except the shielding structures 1508, 1608, 1708 include one or more extensions 1512, 1612, 1712. For example, referring to FIG. 19, the slot-type floating strips 1509 and slot-type grounding strips 1510 of the shielding structure 1508 are formed above the coplanar waveguide structure 1506, and the extensions 1512 extend from above the coplanar waveguide structure 1506 to below (or even with) the coplanar waveguide structure 1506 (i.e., extends downwardly toward the lower substrate 1502 and upper substrate 1504). Referring to FIG. 20, the slot-type floating strips 1609 and slot-type grounding strips 1610 of the shielding structure 1608 are formed below the coplanar waveguide structure 1606, and the extensions 1612 extend from below the coplanar waveguide structure 1606 to above (or even with) the coplanar waveguide structure 1606 (i.e., extends upwardly away from the lower substrate 1602 and upper substrate 1604). Referring to FIG. 21, the slot-type floating strips 1709 and slot-type grounding strips 1710 of the shielding structure 1708 are formed above and below the coplanar waveguide structure 1706, and the extensions 1712 extend from the slot-type floating/grounding strips 1709/1710 above the coplanar waveguide structure 1706 to below the slot-type floating/grounding strips 1709/1710 below the coplanar waveguide structure 1706. The extensions 1512, 1612, 1712 may be coupled to (and/or connected with) the slot-type floating strips 1509, 1609, 1709 and/or slot-type grounding strips 1510, 1610, 1710. The extensions 1512, 1612, 1712 may extend partially or entirely along the height of the coplanar waveguide structures 1506, 1606, 1706 and/or partially or entirely between the slot-type floating/grounding strips 1709/1710 above the coplanar waveguide structure 1706 and the slot-type floating/grounding strips 1709/1710 below the coplanar waveguide structure 1706. In the present embodiments, the extensions 1512, 1612, 1712 are rectangular-shaped. It is contemplated that the extensions 1512, 1612, 1712 may include other shaped extensions, such as circular-shaped, elliptical-shaped, triangular-shaped, other suitable shapes, and/or combinations thereof. Further, similarly to the devices described above, the slot-type floating strips 1509, 1609, 1709 are oriented transversely to the coplanar waveguide structures 1506, 1606, 1706. It is understood that the slot-type floating strips 1509, 1609, 1709 may be oriented differently in other embodiments.

FIGS. 22, 23, and 24 provide transverse cross-sectional views of devices 1800, 1900, and 2000 comprising shielding structures according to various embodiments. Device 1800 comprises a lower substrate 1802, an upper substrate 1804, a coplanar waveguide structure 1806 including one or more conductor lines 1807 a, 1807 b, and a shielding structure 1808 including one or more slot-type floating strips 1809 and one or more slot-type grounded strip extensions 1810. Device 1900 comprises a lower substrate 1902, an upper substrate 1904, a coplanar waveguide structure 1906 including one or more conductor lines 1907 a, 1907 b, and a shielding structure 1908 including one or more slot-type floating strips 1909 and one or more slot-type grounded strip extensions 1910. Device 2000 comprises a lower substrate 2002, an upper substrate 2004, a coplanar waveguide structure 2006 including one or more conductor lines 2007 a, 2007 b, a shielding structure comprising one or more slot-type floating strips 2009 and one or more slot-type grounded strip extensions. The lower substrates 1802, 1902, 2002; upper substrates 1804, 1904, 2004; and coplanar waveguide structures 1806, 1906, 2006 including one or more conductor lines 1807 a, 1807 b, 1907 a, 1907 b, 2007 a, 2007 b are similar to the lower substrates, upper substrates, and coplanar waveguide structures including one or more conductor lines described above.

The shielding structures 1808, 1908, 2008 including the slot-type floating strips 1809, 1909, 2009 are also similar to the shielding structures including slot-type floating strips described above, except the shielding structures 1808, 1908, 2008 are coupled to (and/or connected to) one or more slot-type grounding strip extensions 1810, 1910, 2010. For example, referring to FIG. 22, the slot-type floating strips 1809 of the shielding structure 1808 are formed above the coplanar waveguide structure 1806, and the slot-type grounding strip extensions 1810 extend from above the coplanar waveguide structure 1806 to below (or even with) the coplanar waveguide structure 1806 (i.e., extends downwardly toward the lower substrate 1802 and upper substrate 1804). Referring to FIG. 23, the slot-type floating strips 1909 of the shielding structure 1908 are formed below the coplanar waveguide structure 1906, and the slot-type grounding strip extensions 1910 extend from below the coplanar waveguide structure 1906 to above (or even with) the coplanar waveguide structure 1906 (i.e., extends upwardly away from the lower substrate 1902 and upper substrate 1904). Referring to FIG. 24, the slot-type floating strips 2009 of the shielding structure 2008 are formed above and below the coplanar waveguide structure 2006, and the slot-type grounding strip extensions 2010 extend from the slot-type floating strips 2009 above the coplanar waveguide structure 2006 to below the slot-type floating strips 2009 below the coplanar waveguide structure 2006. The slot-type grounding strip extensions 1810, 1910, 2010 may be coupled to (and/or connected with) the slot-type floating strips 1809, 1909, 2009. The slot-type grounding strip extensions 1810, 1910, 2010 may extend partially or entirely along the height of the coplanar waveguide structures 1806, 1906, 2006 and/or partially or entirely between the slot-type floating strips 2009 above the coplanar waveguide structure 2006 and the slot-type floating strips 2009 below the coplanar waveguide structure 2006. In the present embodiments, the slot-type grounding strip extensions 1810, 1910, 2010 are rectangular-shaped. It is contemplated that the slot-type grounding strip extensions 1810, 1910, 2010 may include other shaped extensions, such as circular-shaped, elliptical-shaped, triangular-shaped, other suitable shapes, and/or combinations thereof. Further, similarly to the devices described above, the slot-type floating strips 1809, 1909, 2009 are oriented transversely to the coplanar waveguide structures 1806, 1906, 2006. It is understood that the slot-type floating strips 1809, 1909, 2009 may be oriented differently in other embodiments.

The devices and structures disclosed herein may be formed using well-known manufacturing processes. Further, the devices and structures disclosed herein may be used in many products, including but not limited to items such as integrated circuits, monolithic microwave integrated circuits, radio frequency transmitters and receivers, radio frequency communication equipment, antennas, circuit boards, amplifiers, modulators, and demodulators. These and other items may be improved by using one or more of the devices and structures disclosed herein. For example, the devices and structures disclosed herein may allow some items to be made smaller, lighter, more efficient, more powerful, more sensitive, less noisy, more selective, faster, or cheaper.

In summary, a device for transmitting a radio frequency signal along a signal line is disclosed. The device includes a signal line that extends along a principal axis. To one side of the signal line is a first dielectric, and to an opposite side of the signal line is a second dielectric. Proximate to the first dielectric is a first ground line, and proximate to the second dielectric is a second ground line. The first and second ground lines are approximately parallel to the signal line. The device has a transverse cross-section that varies along the principal axis.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. 

1. A coplanar waveguide structure comprising: one or more ground lines proximate to one or more signal lines, the signal lines and the ground lines being essentially parallel to each other and oriented substantially along a first direction; a periodic structure included in at least one of the one or more signal lines comprises alternating segments, wherein at least one of the alternating segments extends in a second direction transverse to the first direction.
 2. The coplanar waveguide structure of claim 1 wherein at least one of the one or more ground lines includes a periodic structure comprising alternating segments, wherein at least one of the alternating segments extends in a second direction transverse to the first direction.
 3. The coplanar waveguide structure of claim 1 wherein the alternating segments comprise a first segment and a second segment alternating periodically, the second segment being wider than the second segment.
 4. The coplanar waveguide structure of claim 3 wherein the second segment comprises an extension that includes a rectangular shape, a circular shape, a triangular shape, or any other suitable shape.
 5. The coplanar waveguide structure of claim 4 wherein the extension extends outwardly or inwardly.
 6. The coplanar waveguide structure of claim 1 wherein a transverse cross-section of the at least one signal line including the periodic structure varies periodically over its length.
 7. The coplanar waveguide structure of claim 1 further comprising one or more islands proximate to the one or more signal lines and the one or more ground lines.
 8. The coplanar waveguide structure of claim 7 wherein the one or more islands comprises a conductive material.
 9. The coplanar waveguide structure of claim 1 further comprising one or more floating strips oriented above and/or below the one or more signal lines and the one or more ground lines.
 10. The coplanar waveguide structure of claim 1 wherein the one or more floating strips are oriented transversely to the one or more signal lines and the one or more ground lines.
 11. The coplanar waveguide structure of claim 1 further comprising one or more islands proximate to and one or more floating strips oriented above and/or below the one or more signal lines and the one or more ground lines.
 12. A device comprising: a substrate; an insulator over the semiconductor substrate; a coplanar waveguide structure over the insulator and oriented substantially along a first direction; and one or more slot-type floating strips oriented above and/or below the coplanar waveguide structure in a second direction transverse to the first direction, wherein the one or more slot-type floating strips are located periodically along the first direction.
 13. The device of claim 12 wherein at least one of the one or more slot-type floating strips includes one or more extensions.
 14. The device of claim 12 wherein the one or more slot-type floating strips comprise a conductive material.
 15. The device of claim 12 wherein the coplanar waveguide structure comprises one or more conductor lines, wherein at least one of the one or more conductor lines comprises a periodic structure.
 16. The device of claim 12 further comprising one or more slot-type grounded floating extensions coupled to at least one of the one or more slot-type floating strips, the one or more slot-type grounded floating extensions being oriented in the first direction.
 17. The device of claim 16 wherein the one or more slot-type floating strips are oriented periodically.
 18. A device comprising: a substrate; an insulator over the semiconductor substrate; a coplanar waveguide structure over the insulator and oriented substantially along a first direction; one or more slot-type floating strips oriented above and/or below the coplanar waveguide structure in a second direction transverse to the first direction, wherein the one or more slot-type floating strips are located periodically along the first direction; and one or more slot-type grounding strips oriented above and/or below the coplanar waveguide structure in the first direction, wherein the one or more slot-type grounding strips are coupled to at least one of the one or more slot-type floating strips.
 19. The device of claim 18 wherein at least one of the one or more slot-type grounding strips includes one or more extensions.
 20. The device of claim 18 wherein the one or more slot-type grounding strips are located periodically along the second direction. 